1. Field of Invention
This invention is directed to a method and a tool that can be used in place of a conventional power tong for making up and for breaking out threaded connections in tubular strings used in drilled wells. Specifically, the present invention is directed to a method and a tool for internally gripping and then rotating a tubular segment to make-up or break-out a threaded connection between the tubular segment and a suspended tubular string.
2. Background of the Related Art
Oil field tubular members, e.g., drill pipe, production tubing and casing strings, are generally produced in tubular segments that are threadedly coupled into a tubular string using threaded connections, such as sleeve-type or integral threaded connections, at their ends. Power tongs are machines that may be used to make-up and break-out threaded connections between adjacent tubular segments by gripping a first tubular segment, and by gripping and rotating an adjacent second tubular segment relative to the first tubular segment to either make-up or break-out the threaded connection between the two.
FIG. 1 is a perspective view of a prior art externally gripping power tong 200. The power tong 200 has a drive motor 210 that may be hydraulically or pneumatically-powered, and a gripping assembly mechanically coupled to the motor for gripping and rotating a tubular segment received within the bay 206. A generally “C”-shaped gear housing 212 supports a pair of pivoting doors 214 which may be closed to secure the bay 206 or swung open (as indicated in FIG. 1) to provide access to the bay 206. The bay 206 is generally surrounded by the gear housing 212. The center of the bay 206 is between a pair of generally opposed pivotable gripping jaws 220, each having a generally arcuate gripping surface disposed radially inwardly toward the center of the bay 219.
An externally gripping power tong, like that shown in FIG. 1, is generally supported within a frame or skid that is movably supported on the rig floor so that it can be moved to and withdrawn from well center as needed to make-up or to break-out threaded connections. The frame or skid is generally large and heavy, and takes up a large amount of valuable rig storage space when it is not in use. Also, a conventional power tong, like that shown in FIG. 1, occupies a large amount of space when in use on the rig floor, and the movement of this large piece of equipment to and from well center requires coordination with other equipment and activities on the rig.
Gripping the exterior of the tubular segment being threadably coupled to the tubular string suspended in the well generally avoids interference with or obstruction of fill-up and circulation tools used to intermittently introduce fluid into the bore of the tubular string to maintain fluid levels within the tubular string and to avoid unwanted downhole pressure differentials that may otherwise damage or collapse the tubular string. However, the significant disadvantages of externally gripping power tongs give rise to a need for an alternative device and method for making up and breaking out threaded connections in tubular strings on a rig.
What is needed is a device for gripping and rotating a tubular segment that does not take up a large amount of valuable rig floor space. What is needed is a device for gripping and rotating a tubular segment that does not require movement of rig equipment to well center to grip and rotate tubulars. What is needed is a device for gripping and rotating a tubular segment that facilitates unfettered introduction of fluid into the bore of the tubular string as additional tubular segments are added to the tubular string. What is needed is a device for gripping and rotating a tubular segment that is self-energizing, and that may be adapted for being self-energizing for both making up and breaking out the threaded connection. What is needed is a method of making up and running a tubular string in a borehole that includes the step of supporting an elevator from a top drive assembly using bails, the step of rotatably supporting a self-energizing internally gripping tong from the quill of the top drive generally intermediate the bails, and the step of inserting the internally gripping power tong into the bore of a tubular segment to make-up and torque the threaded connection between the tubular segment and the tubular string.